1. Field of the Invention
The present invention relates to a brake assembly with noise damping and, more particularly, to a brake assembly including a tuned mass damper located inside of a hole formed in a brake component such as a backplate.
2. Background of the Invention
In disc brake assemblies, a rotor rotates with the axle of a wheel to be braked and two friction pad structures are disposed on opposite sides of the rotor. Each friction pad structure comprises a brake pad mounted to a backplate, usually made of steel. The friction pad structures are moved inwardly, toward one another, under the force applied by a hydraulically-actuated piston and related caliper fingers of a caliper mounting structure. When the hydraulic force is released, the pad structures are moved outwardly, away from one another, by return springs.
When the pistons and caliper fingers press the backplates inwardly, the inner surfaces of the brake pads are engaged in frictional, braking contact with the rotor. A relatively high pitched and undesired brake squeal noise can be produced during such braking engagement of the pads on the rotor. The brake squeal noise is produced by vibration of the friction pad structures during braking actuation.
To reduce the undesired brake squeal noise, it is known to use sound-dampening shims positioned both between the hydraulically-actuated piston and the piston engaging surface of the related steel backplate, and also between the caliper fingers and the caliper contact surface of the related steel backplate. One such shim structure is shown in U.S. Pat. No. 5,518,088.
It has also been proposed to attach a sheet metal plate to the backplate, the sheet metal plate having a groove cut therethrough to form tuning fork members of varying length. A damping material is applied to the tuning fork members, and the lengths of the members vary in order to damp particular frequencies of vibrations. See U.S. Pat. No. 6,283,258, assigned to the assignee of the present application.
It is desirable to provide an improved apparatus for sound-dampening brake squeal noise in which the brake squeal noise is reduced, and a variety of brake squeal frequencies may be absorbed.